UScholar Works
 
Filters: Department: "Physics" Collection: "ir_uspace"
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CreatorTitleDescriptionSubjectDate
1 Kieda, David B.Deployment of a pair of 3M telescopes in UtahTwo 3m telescopes are being installed in Grantsville Utah. They are intended for the testing of various approaches to the implementation of intensity interferometry using Cherenkov Telescopes in large arrays as receivers as well as for the testing of novel technology cameras and electronics for grou...Star Base Utah; 3M telescopes; Intensity interferometry; Cherenkov telescopes2008
2 Gondolo, PaoloDUSEL theory white paperThe scientific case for a Deep Underground Science and Engineering Laboratory [DUSEL] located at the Homestake mine in Lead, South Dakota is exceptional. The site of this future laboratory already claims a discovery for the detection of solar neutrinos, leading to a Nobel Prize for Ray Davis. Moreov...DUSEL; Deep Underground Science and Engineering Laboratory; Proton decay2008
3 Gondolo, PaoloEffect of dark matter on the first stars: a new phase of stellar evolutionDark matter (DM) in protostellar halos can dramatically alter the current theoretical framework for the formation of the first stars. Heat from supersymmetric DM annihilation can overwhelm any cooling mechanism, consequently impeding the star formation process and possibly leading to a new stellar ...Dark stars2008
4 Gerton, JordanNanoscale fluorescence microscopy using carbon nanotubesWe demonstrate the first reported use of single-walled carbon nanotubes as nano-optical probes in apertureless nearfield fluorescence microscopy. We show that, in contrast to silicon probes, carbon nanotubes always cause strong fluorescence quenching when used to image dye-doped polystyrene spheres...2008
5 Bromley, Benjamin C.Rise and fall of debris disks: MIPS observations of h and chi Persei and the evolution of mid-IR emission from planet formationWe describe Spitzer MIPS observations of the double cluster, h and X Persei, covering a 0.6 deg2 area surrounding the cores of both clusters. The data are combined with IRAC and 2MASS data to investigate 616 sources from 1.25Y24 m. We use the long-baseline Ks ½24 color to identify two population...Infrared circumstellar matter; Open clusters and associations stars: Individual (NGC 869, NGC 884) planetary systems: Formation, planetary systems: Protoplanetary disks2008
6 Kieda, David B.Search for TeV emission from geminga by the VERITAS observatoryDuring November/December 2007, we observed the region centered on the Geminga Pulsar for 10.4 hours using the VERITAS IACT Observatory. We find no evidence for either steady emission point source emission, or pulsed emission of a point source at the period of the Geminga pulsar (237 msec). The measu...VHE Gamma ray; Geminga Pulsar; VERITAS Observatory; TeV emission2008
7 Gondolo, PaoloSection on prospects for dark matter detection of the white paper on the Status and future of ground-based TeV gamma-ray astronomyThis is a report on the findings of the dark matter science working group for the white paper on the status and future of TeV gamma-ray astronomy. The white paper was commissioned by the American Physical Society, and the full white paper can be found on astro-ph (arXiv:0810.0444). This detailed sec...Annihilations; Dwarf spheroidal2008
8 Gondolo, Paolo; Springer, Robert WayneSite characteristic of Southern Utah sites for astronomical observatoriesThe University of Utah has recently begun construction of a new 0.8m optical/IR robotic telescope to be operated as a regional astronomy resource in the Intermountain West. The new Southern Utah Observatory (SUO) will require a high altitude (>3000 m) site with excellent atmospheric seeing, favorab...2008
9 Kieda, David B.Status of the VERITAS observatoryAbstract. VERITAS, an Imaging Atmospheric Cherenkov Telescope (IACT) system for gammma-ray astronomy in the GeV-TeV range, has recently completed its first season of observations with a full array of four telescopes. A number of astrophysical gamma-ray sources have been detected, both galactic and e...2008
10 Vardeny, Zeev Valentine; Nahata, AjayThermal emission from metallic films perforated with subwavelength hole arraysThis report presents an overview of our study on the optical transmission and thermal light emission properties of subwavelength hole arrays fabricated in a square lattice with 4 um periodicity. The structures were fabricated in thin aluminum (Al) films on silicon (Si) substrates using conventional ...2008
11 Kieda, David B.Toward a revival of stellar intensity interferometryBuilding on technological developments over the last 35 years, intensity interferometry now appears a feasible option by which to achieve diffraction-limited imaging over a square-kilometer synthetic aperture. Upcoming Atmospheric Cherenkov Telescope projects will consist of up to 100 telescopes, ...Intensity interferometry; Air Cherenkov Telescope2008
12 Bromley, Benjamin C.Variations on debris disks: icy planet formation at 30-150 AU for 1-3 M. main-sequence starsWe describe calculations for the formation of icy planets and debris disks at 30-150 AU around 1-3 M. stars. Debris disk formation coincides with the formation of planetary systems. As protoplanets grow, they stir leftover planetesimals to large velocities. A cascade of collisions then grinds the l...Icy planets; Planet formation; Debris disks; Main-sequence stars2008
13 Vardeny, Zeev ValentineBelow-gap excitation of ∏-conjugated polymer-fullerene blends: implications for bulk organic heterojunction solar cellsWe used a variety of optoelectronic techniques such as broadband fs transient and cw photomodulation spectroscopies, electroabsorption, and short-circuit photocurrent in bulk heterojunctions organic solar cells for studying the photophysics in ∏-conjugated polymer-fullerene blends with below-gap...pi-conjugated polymers; Fullerene blends; Below-gap excitations; Bulk heterojunctions; Bulk organic heterojunction solar cells; Photophysics2008-07
14 Mishchenko, EugeneCharge response function and a novel plasmon mode in graphenePolarizability of noninteracting 2D Dirac electrons has a 1 1 / √qv-ω singularity at the boundary of electron-hole excitations. The screening of this singularity by long-range electron-electron interactions is usually treated within the random phase approximation. The latter is exact only in the ...Excitons; Random phase approximation2008-04
15 Gondolo, PaoloDark matter and the first stars: a new phase of stellar evolutionA mechanism is identified whereby dark matter (DM) in protostellar halos dramatically alters the current theoretical framework for the formation of the first stars. Heat from neutralino DM annihilation is shown to overwhelm any cooling mechanism, consequently impeding the star formation process and ...Dark stars2008-02
16 Gondolo, PaoloDark stars: dark matter in the first stars leads to a new phase of stellar evolutionThe _x000C_first phase of stellar evolution in the history of the universe may be Dark Stars, powered by dark matter heating rather than by fusion. Weakly interacting massive particles, which are their own antiparticles, can annihilate and provide an important heat source for the fi_x000C_rst stars...Dark stars; WIMP; Weakly interacting massive particles2008-06
17 Rogachev, AndreyDetermination of the superconductor-insulator phase diagram for one-dimensional wiresWe establish the superconductor-insulator phase diagram for quasi-one-dimensional wires by measuring a large set of MoGe nanowires. This diagram is roughly consistent with the Chakravarty-Schmid-Bulgadaev phase boundary, namely, with the critical resistance being equal to RQ ¼ h=4e2. Deviations fr...One-dimensional wires; Superconductor-insulator phase diagram; MoGe; Chakravarty-Schmid-Bulgadaev; Phase boundary2008-11
18 Gondolo, PaoloDirect detection of neutralino dark matter in nonstandard cosmologiesWe compute the neutralino direct detection rate in nonstandard cosmological scenarios where neutralinos account for the dark matter of the Universe. Significant differences are found when such rates are compared with those predicted by the standard cosmological model. For b-ino-like neutralinos, the...Neutralinos2008-02
19 Gondolo, PaoloDirectional recoil rates for WIMP direct detectionNew techniques for the laboratory direct detection of dark matter weakly interacting massive particles (WIMPs) are sensitive to the recoil direction of the struck nuclei.We compute and compare the directional recoil rates dR/d cosθ, (where θ is the angle measured from a reference direction in th...WIMP; Weakly interacting massive particles; WMAP 3; Directional recoil; Halo models2008-02
20 Boehme, ChristophEffect of exchange coupling on coherently controlled spin-dependent transition ratesThe effect of exchange interactions within spin pairs on spin-dependent transport and recombination rates through localized states in semiconductors during coherent electron-spin resonant excitation is studied theoretically. It is shown that for identical spin systems, significant quantitative diff...Spin coherence; Electron spin nutations2008-06
21 Sokolsky, PierreFirst observation of the Greisen-Zatsepin-Kuzmin suppressionThe High Resolution Fly's Eye (HiRes) experiment has observed the Greisen-Zatsepin-Kuzmin suppression (called the GZK cutoff) with a statistical significance of five standard deviations. HiRes' measurement of the flux of ultrahigh energy cosmic rays shows a sharp suppression at an energy of 6 x 10^1...Extensive air showers; Suppression; Energy spectrum; Fluorescence; GZK cutoff2008-03
22 Saam, Brian; Pugmire, Ronald J.Gas-phase spin relaxation of 129XeWe have completed an extensive study of 129Xe longitudinal spin relaxation in the gas phase, involving both intrinsic and extrinsic mechanisms. The dominant intrinsic relaxation is mediated by the formation of persistent Xe2 van der Waals dimers. The dependence of this relaxation on applied magnetic...129Xe; Gas-phase spin relaxation2008-10
23 Wu, Yong-ShiHigh-precision quasienergies for a driven two-level atom at the two-photon preresonanceA computation with unprecedented precision is presented for quasienergies of a two-level atom in a monochromatic radiation on the basis of a recently obtained exact expression [D.-S. Guo et al., Phys. Rev. A 73,023419 (2006)]. We start with the proof of an expression theorem. With this theorem the ...Quasienergies; Preresonance; Floquet periodicity2008-02
24 Boehme, ChristophLong-lived spin coherence in silicon with an electrical spin trap readoutPulsed electrically detected magnetic resonance of phosphorous (31P) in bulk crystalline silicon at very high magnetic fields (B0 > 8:5 T) and low temperatures (T = 2:8 K) is presented. We find that the spin-dependent capture and reemission of highly polarized (>95%) conduction electrons by equall...Spin coherence2008-11
25 Vardeny, Zeev ValentineMagnetic field effects in ∏-conjugated polymer-fullerene blends: evidence for multiple componentsWe studied magnetoconductance (MC) and magnetoelectroluminescence (MEL) in organic diodes from blends of ∏-conjugated polymers and fullerenes at various concentrations, c. The MC response is composed of several components that depend on the applied bias voltage and c. A dominant positive low-field...pi-conjugated polymers; Fullerene blends; Magnetic field effects; Magnetoconductance; Magnetoelectroluminescence; MC; MEL; Organic magnetoresistance; OMAR; Organic diodes2008-12
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